Pulverizer-mill



I. W. FULLER.

PULVERIZER MILL.

APPLICATION FILED JUNE I, I918.

I 1,345,082. Patented June 29, 1920.

2 SHEETS-SHEET I- l/VI/E/V TOR I\ I vfiwm A TTOR/VEI;

1. W/FULLERQ PULVERIZER MILL.

APPLICATION FILED JUNE 1, 1918.

1,345,082. I Patented June 29, 1920.

2 SHEETSSHEET 2.

' INVENTOR UNITED STATES PATENT- OFFICE.

JAMES W. FULLER, OF CATASAUQUA, PENNSYLVANIA, ASSIGNOR T0 FULLER- LEHIGH COMPANY, A CORPORATION OF PENNSYLVANIA.

PULVERIZER-MILL.

Specification of Letters Patent.

Patented June 29, 1920.

Application filed June 1, 1918. Serial No. 237,686.

.To all whom it may concern Be it known that I, JAMES IV. FULLER, a citizen of the United States, residing at Catasauqua, in the county of Lehigh and State of Pennsylvania, have invented certain new and useful Improvements in Pulverizer-Mills; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to improvements in pulverizer mills and particularly to a construction whereby the efficiency of such mills in producing pulverized material of reat fineness is considerably increased.

I or the purpose of illustrating an application of the invention, I have selected a pulverizer mill of the general type shown, for example, in my United States Patents Nos. 849,779, 922,468 and 1,039,721. Such mills consist essentially of a pulverizing zone containinga stationary grinding ring in which a series of balls is caused to revolve by means of pushers fastened to a yoke casting keyed to the center or main shaft of the mill; and a screening chamber placed above the pulverizing zone. and in which there is a rotary fan comprising a series of blades which tend to lift the material out of the pulverizing zone into the path of a second series of blades placed above the first series and which direct-the material against and through a cylindrical screen placed near the outer wall of the screening chamber. A fan housing is commonly provided below the pulverizing zone, and this housing is in direct communication with ,the screening chamber between the screen and the wall so that it receives the pulverized material which has been screened. A rotary fan is provided in this lower fan housing for aiding the discharge of the pulverized material.

In the operation of machines of the abovementioned type, known. on the market as Fuller mills, the pulverized material is lifted from the pulverizing zone into the screening chamber and is discharged from the machine largely by flotation in the upwardly and then outwardly and downwardly moving currents of air produced by the series of fans, but in addition to this flotation in the air currents the first series of upwardly inclined fan blades acts by striking the particles of pulverized material to lift a great deal of the material which is too coarse to float in the air currents well up into the screening chamber and fully into the path of the overlapping blades of the second fan. These blades in turn throw this material against the screen, and those particles which are fine enough to pass through the meshes of the screen are discharged, while the larger particles fall from the screen back into the pulverizing zone where they are subjected to further grinding and again lifted into the screening chamber to be discharged if fine enough.

In accordance with the present invention, there is provided in combination with a pulverizer mill of the general type referred to, and immediately above the pulverizing zone a separating chamber or settling zone in which the coarser particles may be separated by gravity to fall back into the pulverizing zone before encountering the blades of the second fan. The wall of the separating section is provided with a series of axially extending ports forming communicating passages between the lower fan housing and the section above the settling zone. The interior of the separating chamber is open at top and bottom, so that the pulverizing zone is in direct communication. through this section, with the chamber above. The separating chamber contains the first or lift-- ing series of fan blades, while the blades of the second fan alone are within the superposed chamber. The provision of a separating chamber of this character in a pulverizer mill of the type described enables one to obtain with much less consumption of power, a finished product having a very high percentage of extremely fine material.

The particular nature of the present invention, as well as other advantages thereof will appear more clearly from adescription of certain preferred embodiments as shown in the accompanying drawings in which Figure l is an elevation in section of a pulverizer mill provided with one form of separating chamber and screening chamber, and Fig. 2 is a similar view of a mill provided with a modified construction of separating chamber and a diiferent screening chamber.

Referring to the drawings in which similar reference characters denote similar parts in each of the figures, 10 represents the base of the machine, and 11 a standard attached to the base and upon the u per edge of which is mounted a ring 12. 3n top of this ring is a casing '13, the casing and ring being attached to the standard by bolts 14, or in any other convenient manner. Supported upon the base of the casing 13 is a grinding ring 15, but the latter is spaced from the vertical wall of the casing, or furnished with apertures along its outer edge to provide passageways 16 extending through the section of the apparatus formed by the casing 13 p and opening intothe fan chamber formed between the bottom of this casing and the top of the standard, which chamber is bounded upon the outside by the ring 12.

Mounted upon the upper edge of the casing 13 is a cylindrical casing 17 forming the wall of the separating chamber or settling zone 17 of the present invention. The casing 17 should preferably be provided with depressions or ridges as at 18 to engage corresponding ridges or depressions formed on the top of the ring 15 and the casing 13 in order that there may be no horizontal displacement of any of these parts with respect to theothers. The bottom of the casing 17 is provided with a flange or ears as shown at 19 and through which bolts 20 may be passed to engage corresponding members formed at the top of the casing 13. By virtue of the construction just described, the section of the casing surroundingthe separating zone 17 is securely attached to the top of the easing within which is the pulverizing or grinding zone of the apparatus. The casing 17 is also provided with axially extending passageways as at 21 and these passageways register with the corresponding passageways 16 in the section 13.11

On top of the casing'17 is mounted a screening chamber which ma be of an preferred construction, and 1n Fig. 1 is shown as comprising a circular frame 22 which is attached to the top of the section 17 by bolts 23,-and which serves to support a screen'24 which may be of any meshv suitable to pass particles of the desired size. The frame is surrounded by an outer Wall 25, and the bottom portion of the frame 22 is provided with passageways registering with the passageways 21 in the section 17 and opening into the space between the screen 24: and the wall 25. These passageways in connection with the corresponding passageways in the casing 13 provide discharge openings from the outer portion of the screening chamber to the chamber formed between the base of the casing 13 and the top of the standard, from which latter chamber the pulverized material may be discharged through' spout 26 which may be of anyI desired construction.

aterial is fed to the. apparatus by a suitable feeding device 27'which is mounted ona cover plate 28 attached to the top of the frame 22. Attached to the under side of this cover plate is a funnel 29 which extends through the screening chamber for a considerable distance and serves to direct the incoming material toward the center of the ap-' ing-mounted in a suitable bearing 32in the base of the apparatus. A drivlng pulley is mounted upon the shaft within the standard 11. The rotating portions of the apparatus are mounted upon the shaft 31 and comprise a frame or yoke 34 provided at its lower end with radial arms 35 to the outer ends of which are connected pusher members for engaging and driving the grinding balls 36 as the shaft is rotated. The intermediate portion of the frame or yoke 34 carries a number of inclined lifting blades 37 which extend substantially through the settling zone portion of the apparatus, the

lower ends of these blades terminating above the contacting surfaces of the grinding balls 36 and the grinding ring 15, while their upper ends terminate below and just inside of the lower ends of radial fan blades 38 which are mounted within the-screening chamber upon vertical standards formed at the upper end of the yoke 34:. The shaft 31 also carries within the chamber surrounded by the ring 12 a disk 39 provided witha number of vertical fan blades 40, the purpose of which is to assist in the discharge of the pulverized material, as in the machine of my prior Patent No. 1,039,721.

Fig. 2 represents a modification of the invention in which the separating zone and the superposed chamber are formed within an integral casing 50, which at its lower end is attached to the top of the casing 13 forming the wall of the pulverizing zone portion of the apparatus. In this modification of the invention, the cylindrical wall 25' which corresponds to the Wall 25 of Fig. 1 surrounds the portion of the casing50 which constitutes the wall ofthe separating zone 50 as well as the superposed chamber, and the bottom portion of this casing is provided with apertures 51 which register with the passageways 16 in the casing portion 13. It is found in practice that in some cases the screen 24 can be dispensed with, and the pulverized material will be simply floated in the moving air currents out of the upper chamber of the apparatus, all of the particles which should be returned to the pulverizing zone falling back by gravity through the settling zone to be reground. In other cases, it is found advisable when .baflies such as shown at 52 in Fig. 2 may be used in place of these screens 24.

In the operation of the apparatus shaft 31 and the moving parts'carried thereby are driven by a belt passing over the pulley 33 and the desired material is regularly supplied to the machine by the feeding mechanism 27 which is under the control of the operator. If in the material supplied to the machine there are particles fine enough to float in the upwardly and then outwardly and downwardly moving air currents, these particles as they are discharged from the funnel 29 may be immediately separated and discharged before reaching the pulverizing zone. The larger particles will fall through the separating zone 17 of the apparatus into the pulverizing zone where they will ultimately come between the grinding ring and the balls and be reduced in size. The pulverized material will be lifted from the zone of operation of the grinding balls by the upwardly moving currents of air due to the action of the several fans. Carried by these air currents, the pa rticles will traverse the settling zone and during their passage through this zone,the relatively large and heavier particles will be separated by gravity and will fall back into the pulverizing zone and be reground between the balls and the grinding ring. It results from the provision of the separating zone, that the pulverized material reaching the superposed chamber is practically all of a fineness such as to float in the moving currents of air. In types of apparatus, such as shown in my prior patents, which have no settling zone, a considerable number of particles too large to pass through the screen may be driven against the screen by the ac tion of the upper fan blades. These larger particles not only tend to obstruct the passage of the smaller particles, but-may even become wedged into the meshes of the screen and thus in effect, permanently close them, and thereby render the screening surface of less extent so that the effectiveness of the apparatus is materially lessened. All of the material passing with the air currents out of the superposed chamber is drawn through the communicating passageways in the different sections of the apparatus and into the chamber beneath the pulverizing zone from which the material will be discharged through the spout 26 in a constant stream, this discharge being aided by the vertical blades 40 on the rotating disk 39.

The operation of the apparatus shown in Fig. 2 will be substantially the same as that shown in Fig. 1, except that instead of being screened, the material will be floated directly, without screening, through the baflles and will pass into the discharge chamber. As explained in connection with the description of Fig. 2, the screen maybe omitted, and it is not necessary in all cases to provide the balfles as a substitute, since on account of the fact that the over-size particles fall back into the pulverizing zone from the settling zone, all ofthe material discharged from the upper portion of the apparatus will be pulverized to a uniform degree of fineness. The form of construction shown in Fig. 2 possesses certain advantages as the use of separate casings around the separating zone and the screening chamber is eliminated, and the construction is thereby simplififed. In any case, whether a. screen is used or not, the character of the construction is such that the pulverized material is lifted from thepulverizing zone by the air currents produced by the several fans, and is carried vertically through the settling zone for a sufficient distance to permit the separation of the heavier particles by gravity. It is then deflected outwardly in the superposed chamber and is finally drawn downwardly through the described passages and is discharged. It will be observed that, while the preferred arrangement of fans comprises first a lifting fan immediately above the pulverizing zone; second, a deflecting fan in the chamber above the settling zone, and, third, a discharge fan near the discharge outlet of the apparatus, nevertheless one or more of these fans may be omitted and other arrangements of fans may be made to produce the posed chamber for maintaining a flow of air upwardly from the zone of action of the grinding means through the settling chamber and outwardly from the superposed chamber to carry pulverized material out of the mill.

2. In a pulverizer mill, the combination of a base, a cylindrical casing mounted upon the base, grinding elements in the casing, a

, second cylindrical casing concentrically mounted on the first named casing and inclosing a settling chamber, a third cylindrical casing concentrically mounted on the second named casing and inclosing a superposed chamber, and means for maintaining a flow of air upwardly from the grinding elements through the settling chamber and outwardly from the superposed chamber to carry pulverized material out of the mill.

3. In a pulverizer mill, means for grinding material, a casing above the grinding means inclosing a settling chamber, a casing below the grinding means inclosing a discharge chamber, means for maintaining a flow of air upwardly from the zone of action of the grinding means through theseparating chamber, and means for conducting the air to the discharge chamber after it passes through the separating chamber to carry pulverized material out of the mill.

4. In a pulverizer mill, grinding elements within a grinding zone, a settling chamber above the grinding zone, a chamber superposed upon the settling chamber, a discharge chamber beneath the grinding zone having communication with the superposed chamber, and means for maintaining a flow of air upwardly from the grinding zone through the settling chamber and outwardlyfrom the superposed chamber and downwardly to the discharge chamber to dischsirge finely pulverized material from the mi 1. a

5. In a pulverizer mill, grinding elements within a grinding zone, a cylindrical casing above the grinding zone inclosing a settling chamber, a second cylindrical casing superposed upon the first'named casing, a series of rotating blades in the settling chamber arranged to produce upwardly directed air currents to lift the .finely pulverized material therethrough, and a second series of rotating blades in the'superposed casing arranged to deflect outwardly therefrom the air currents carrying the finely pulverized maltlerial to discharge the same from the m1 6. In a pulverizer mill, grinding elements within a grinding zone, a settling chamber abovethe grinding zone, achamber superposed upon the settlin chamber, means for: maintaining a flow 0% air upwardly from the grinding zone through the settling chamber and out of the superposed chamber to float finely pulverized material out of the machine and bafile plates in the path of exit from the superposed chamber.

7 In a pulverizer mill, grinding elements within a grinding zone, a settlin chamber above the grinding zone, a cham er superposed upon the settlin chamber, a series of rotating blades in t e settling chamber arranged to produce upwardly directed air currents tolift the finely pulverized mate'- rial therethrough, a second series of rotating blades in-the superposed chamber arranged to deflect outwardly the air currents carrying the finely pulverized material to discharge the same from the machine, and baflle plates in the path .of exit from the superposed chamber.

8. In a pulverizer mill, the combination of a base, a cylindricalcasing mounted upon the base and inclosing a discharge chamber, a second cylindrical casing mounted upon the first named casing and provided with vertical passageways in its wall, a circular grinding ring within the second named casing, grinding elements cooperating with the grinding ring, a third cylindrical casing concentrically mounted upon the second named casing inclosing a settling chamber and provided with vertical passageways in its wall, registering with the passageways in the wall of the second named casing, a cylindrical frame concentrically mounted upon the third casing forming an upper chamber and having passageways at its lower end, registering with the passageways in the wall of the third casing, a series of rotating blades in the settling chamber, arranged to produce upwardly directed air currents to lift the finely pulverized material therethrough, a second series of rotating blades in the upper chamber, arranged to deflect outwardly the air currents carrying the finely pulverized material, and a third series of rotary blades within the discharge chamber arran ed to draw the air currents downwardly t rough the passageways in the casings whereby material may be discharged from the mill.

9. In a pulverizer mill, grinding elements within a grinding zone, a settling zone above the grinding zone and of sufficient height to permit the separation of insufliciently ground particles by gravity, means for withdrawing finely pulverized material from the grinding zone comprising a lifting fan immediately above the grinding zone and adapted to maintain an upwardly directed flow of air from said grinding zone through the settling zone, and a deflecting fan above the settling zone and adapted to deflect the air currents outwardly to discharge the pulverized material from the mill. i

10. In a pulverizer mill, grinding elements within a grinding zone, a settling zone above the grindingzone and of sulficient height to permit the separation of insufficiently ground particles by gravity, a superposed chamber above the settling zone, means for withdrawing finely pulverized material from the grinding zone, comprising a lifting fan immediately above the grinding zone and adapted to maintain an upwardly directed flow of air from said grinding zone through the settling zone, a deflecting fan above the lifting fan and adapted to deflect air currents outwardly, a discharge chamber below the grinding zone and having communication with the superposed chamber, and a discharge fan in the discharge chamber for drawing the air into the last named chamber to discharge the pulverized material from the mill.

11. In a pulverizer mill, the combination of a base, a cylindrical casing mounted upon the base and provided with vertical passageways in its wall, a circular grinding ring within the casing, grinding elements cooperating with the grinding ring, a second cylindrical casing concentrically mounted upon the first named casing, inclosing a settling chamber and provided with verticalpassageways in its wall, registering with the passageways in the wall of the first named casing, a cylindrical frame concentrically mounted upon the second casing forming an upper chamber and having passageways at its lower end, registering with the passagewa s in the wall of the second casing, a sha t centrally mounted in the mill, means on the shaft for moving the grinding elements, and means also mounted a grinding ring within the casing, grinding elements cooperating with the-ring, a second casing mounted upon the upper end of the first named casing, a portion of said second casing forming the bounding wall of a separating zone and the upper portion of said casing being provided with apertures through which pulverized material may be discharged, a third casing surrounding said second casin to form a chamber within which pulverized material may be collected, a shaft extending through said first and second casings, means on the shaft for moving said grinding elements and means also mounted on the shaft for maintaining a flow of air upwardly from the grinding zone into the upper portion of the second casing and outwardly therefrom to discharge the material from the machine.

In testimony whereof I affix my signature.

JAMES WV. FULLER. 

